Rf Feedthrough - Agilent Technologies 8753ET User Manual

Making Mixer Measurements
Isolation Example Measurements
Figure 2-35 Example Mixer LO to RF Isolation Measurement

RF Feedthrough

The procedure and equipment configuration necessary for this measurement are very similar to those of the
previous LO to RF Isolation procedure, with the addition of an external source to drive the mixer's LO port as
we measure the mixer's RF feedthrough. RF feedthrough measurements do not use the frequency offset
mode.
1. Select the CW LO frequency and source power from the front panel of the external source.
CW frequency = 300 MHz
Power = 10 dBm
2. Initialize the analyzer by pressing
3. To select the analyzer frequency range and source power, press:
Start 10 M/
Stop 3000
Power 0 PWR RANGE MAN
This source stimulates the mixer's LO port.
4. To select a ratio B/R measurement, press:
Meas INPUT PORTS
NOTE Isolation is dependent on LO power level and frequency. To ensure good test results, you
should choose these parameters as close to actual operating conditions as possible.
5. Make the connections as shown in
2-46
.
Preset
M/
x1
B/R
Figure 2-36.